Generally, a gabion or gabion mesh is well known as a basket or cage filled with earth or rocks, and has basic units each of which takes the shape of a rectangle by bending two special zinc-coated steel wires or two steel wires with PVC coating further formed thereon, or a hexagon by twisting two steel wires in such a manner that the steel wires overlap with each other. Among them, a hexagonal gabion has a firm twisted structure formed by the two steel wires, and thus, is characterized in that it has a higher strength over and is stronger than a rectangular gabion. Therefore, the hexagonal gabion is recently preferred to the rectangular gabion.
As shown in FIG. 1, the hexagonal gabion is formed in such a manner that two steel wires mutually forms a twisted structure, branch off from each other and then form another identical twisted structure in cooperation with other adjacent steel wires, and subsequently branch off from each other again and then form a further identical twisted structure in cooperation with the previous adjacent steel wires or other adjacent steel wires, thereby consecutively repeating such processes. Consequently, such hexagonal basic units are formed both in the right and left direction and in the fore and aft direction, and mutually establish a consecutive connection relationship among them both in the right and left direction and in the fore and aft direction, resulting in a large gabion in the form of a steel wire mesh. At this time, the two steel wires can be differentiated into an upper steel wire A guided by an upper slider and a lower steel wire B guided by a lower slider in view of the manufacturing process of the gabion.
Further, FIG. 2 shows an improved version of such a conventional hexagonal gabion. The improved gabion is formed by inserting an additional transverse steel wire C into a twisted structure of upper and lower steel wires A and B to halve the size of a hexagon, so that the gabion can be filled with smaller fillers.
Nowadays, such a hexagonal gabion has been used in a variety of applications by using the hexagonal mesh structure. This hexagonal gabion is most widely used in the field of engineering and construction structures. In this field, for example, a gabion inclination (slope) is formed to protect a cut surface of earth and rocks in a case where there is a risk of collapse and falling rocks. Alternatively, if construction of a revetment for a road or cliff is required, a gabion mesh is assembled and filled with gravel or waste rocks (crushed rocks) having a size of 100 to 300 mm to construct a revetment. Further, in a case where a scour phenomenon has occurred or may occur in a dam or river conservation structure, a gabion mesh is assembled and filled with fillers to prevent the scour phenomenon in the dam or river conservation structure.
Particularly, when a revetment or the like is constructed as an engineering and construction structure, fillers for the revetment are gravel or crushed rocks. Thus, underground water permeating from the ground can freely flow through spaces among the fillers, thereby achieving natural drain. This eliminates a possibility that water pressure is produced inside a wall surface of the revetment. Accordingly, there is an advantage in that collapse due to water pressure can be prevented. Therefore, a gabion revetment is recently admitted as having safety higher than that of other engineering and construction structures, and also appraised as having superior performance.
Moreover, in the engineering and construction structure using the gabion mesh, ambient earth and sand or the like will be gradually filled into spaces among the empty spaces among the fillers, thereby providing soil and environments in which ambient plants can sprout and grow. Thus, there is an advantage in that the structure using the gabion mesh has superior environment-friendliness to similar structures such as concrete revetments or stone reinforcement walls in view of ecology. Therefore, the structure using the gabion mesh is recently widely used as an environment-friendly engineering and construction structure in advanced countries including Europe.
However, even though the gabion mesh has superior environment-friendliness as above, it has several critical problems due to limitations on its basic configuration as follows.
First, in such a conventional gabion mesh, both longitudinal steel wires A and B cannot be continuously supplied but one of the steel wires is cut and then supplied. This is because spirally twisted structures of the conventional gabion mesh continuously proceed only in one direction and the upper steel wire A should be cut to be relatively short and then supplied in order to form the twisted structures by consecutively spirally rotating the upper steel wire A together with the lower steel wire B in one direction while fixing the lower steel wire B as a reference. Nowadays, the upper steel wire A is called “spring steel wire” and is generally used after being cut to be remarkably shorter than the lower steel wire B.
Further, in manufacturing such a conventional gabion mesh, only an intermittently automated process rather than a fully automated process can be employed. This is because a conventional method for manufacturing the gabion mesh employs the shortly cut upper steel wire A, a plurality of upper steel wires A should be generally supplied until the gabion mesh is completely manufactured using a single lower steel wire B, and respective tie operations for the upper steel wires A to the lower steel wire B should be manually performed. Thus, there is a disadvantage in that in manufacturing the conventional gabion mesh, the manufacturing process cannot be fully automated.
Furthermore, there is a disadvantage in that skilled workers are required for manufacturing the conventional gabion mesh. This is because, upon manufacture of the conventional gabion mesh, the upper steel wires A should be repeatedly coupled to the upper slider during the manufacture thereof, and such coupling operations make the automation of the manufacturing process difficult and require craft of skilled workers.
In addition, there is a critical disadvantage in that the method for manufacturing the conventional gabion mesh has very low productivity. This is because the manufacturing process of the conventional gabion mesh is performed intermittently and depends on a partially automated process, at least two or three skilled workers are required according to the size of the gabion mesh, and it takes at least 20 to 30 minutes whenever the aforementioned coupling process is performed even by such skilled workers.
Since these problems with the manufacturing process result from the configuration itself of the conventional gabion mesh, there are insoluble limitations on the problems so far as the coupling structure of the gabion mesh or each unit of the gabion mesh is not fundamentally changed.